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18 Troubleshooting and Fault Clearing Procedures
Table 3-A Continued
Summary of Fault Symptoms and Potential Solutions
SYMPTOMS
The Power Supply SRU is equipped with a power-on LED indicator built into the circuit breaker on the
front panel. The breaker is intended to trip if an overcurrent condition occurs (10 A).
The Loft Power Supply (one per cabinet) is fused for protection against over-voltage conditions. It has
a green LED that indicates normal operation. If the fuse blows, the Power Supply must be removed. A
reserve Power Supply SRU is provided in the bottom shelf of one of the cabinets and acts as a hot
standby should any of the Loft Power Supplies fail.
Power down the system before taking any action that may cause a nonfunctioning
Power Supply SRU to become active (actions like reseating the SRU or switching it
on). Power Supply SRUs should not be switched off or on while the system is operational, because
such an event causes a current surge that can trip the switches on other Power Supply SRUs to the
off position.
None of the fans in a cabinet
is working, and the LED
display on the Power Supply
units are not lit.
None of the fans in a cabinet
is working, but the LED
displays on the Power Supply
units are lit.
Practice 450-1011-501
PROBABLE CAUSES
The power cord is not plugged Plug the cord into the ac outlet.
into the ac outlet.
The power cord is not plugged Plug the power cord into the input
into the input jumper assembly. jumper assembly.
The switch on the input jumper Switch the power ON.
assembly (where so equipped)
is switched OFF.
The power cord is defective.
There is a power fault in a
horizontal jumper assembly.
There is a hardware fault in the
cabinet backplane.
CORRECTIVE ACTIONS
Power the system down, detach the
power cord, and use a multimeter to
check the power cord for an open or
shorted circuit. Replace the cord if it
is defective.
Replace the horizontal jumper
assembly.
Replace the cabinet.
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